is_nothrow_constructible.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2021 Tobias Hienzsch
 
#ifndef TETL_TYPE_TRAITS_IS_NOTHROW_CONSTRUCTIBLE_HPP
#define TETL_TYPE_TRAITS_IS_NOTHROW_CONSTRUCTIBLE_HPP
 
#include <etl/_config/all.hpp>
 
#include <etl/_type_traits/bool_constant.hpp>
#include <etl/_type_traits/declval.hpp>
#include <etl/_type_traits/remove_all_extents.hpp>
 
namespace etl {
 
namespace detail {
template <bool, typename T, typename... Args>
struct nothrow_constructible_impl : false_type { };
 
template <typename T, typename... Args>
struct nothrow_constructible_impl<true, T, Args...> : bool_constant<noexcept(T(declval<Args>()...))> { };
 
template <typename T, typename Arg>
struct nothrow_constructible_impl<true, T, Arg> : bool_constant<noexcept(static_cast<T>(declval<Arg>()))> { };
 
template <typename T>
struct nothrow_constructible_impl<true, T> : bool_constant<noexcept(T())> { };
 
template <typename T, size_t Size>
struct nothrow_constructible_impl<true, T[Size]> : bool_constant<noexcept(remove_all_extents_t<T>())> { };
 
#if defined(__cpp_aggregate_paren_init)
template <typename T, size_t Size, typename Arg>
struct nothrow_constructible_impl<true, T[Size], Arg> : nothrow_constructible_impl<true, T, Arg> { };
 
template <typename T, size_t Size, typename... Args>
struct nothrow_constructible_impl<true, T[Size], Args...>
    : bool_constant<(nothrow_constructible_impl<true, T, Args>::value && ...)> { };
#endif
 
template <typename T, typename... Args>
using is_nothrow_constructible_helper = nothrow_constructible_impl<__is_constructible(T, Args...), T, Args...>;
} // namespace detail
 
/// \brief The variable definition does not call any operation that is not
/// trivial. For the purposes of this check, the call to etl::declval is
/// considered trivial.
template <typename T, typename... Args>
struct is_nothrow_constructible : detail::is_nothrow_constructible_helper<T, Args...>::type { };
 
template <typename T, typename... Args>
inline constexpr bool is_nothrow_constructible_v = is_nothrow_constructible<T, Args...>::value;
 
} // namespace etl
 
#endif // TETL_TYPE_TRAITS_IS_NOTHROW_CONSTRUCTIBLE_HPP